Prospects for pilot plants based on the tokamak, spherical tokamak and stellarator

Abstract

A potentially attractive next-step towards fusion commercialization is a pilot plant, i.e., a device ultimately capable of small net electricity production in as compact a facility as possible and in a configuration scalable to a full-size power plant. A key capability for a pilot plant program is the production of high neutron fluence enabling fusion nuclear science and technology (FNST) research. It is found that for physics and technology assumptions between those assumed for ITER and nth-of-a-kind fusion power plant, it is possible to provide FNSTrelevant neutron wall loading in pilot devices. Thus, it may be possible to utilize a single facility to perform FNST research utilizing reactor-relevant plasma, blanket, coil, and auxiliary systems and maintenance schemes while also targeting net electricity production. In this paper three configurations for a pilot plant are considered: the advanced tokamak (AT), spherical tokamak (ST), and compact stellarator (CS). A range of configuration issues are considered including: radial build and blanket design, magnet systems, maintenance schemes, tritium consumption and self-sufficiency, physics scenarios, and a brief assessment of research needs for the configurations.

Detection of Disruptions in the High-β Spherical Torus NSTX

“…This is an effective means of driving current and supplying power to the relatively cold plasma, and can result in a substantial extension of the disruption phase, during which detection can often be easily accomplished. However, if there were no solenoid, as is common in the design of ST configurations for the FNSF/CTF [156][157][158][159], pilot plant [160], or reactor [161,162] missions, the disruption process may be much faster, and detection significantly more difficult (see Refs [163] for a description of the CTF/FNSF mission). The extensive non-inductive capabilities [164] of NSTX-Upgrade [127] should allow these studies of disruption detection in high-β, 100% non-inductive fraction discharges with solenoid-based I P feedback control disabled.…”

State-space Coil Modelling in Plasma Magnetic Confinement Devices

“…This fact makes stellarators a great alternative to tokamaks, with relevant progresses in the study of the physics of magnetically confined plasmas on these devices in the last years. Besides, its ability to operate in continuous mode -tokamaks are inherently pulsed devices-would allow a higher commercial profitability [5]. The studies presented in this paper have been performed for the UPV/EHU Stellarator ULISES (Ultra-Low Iota Super Elongated Stellarator), fully designed and constructed by the Automatic and Control Group of the UPV/EHU in collaboration with the EURATOM-CIEMAT (see Figure 1).…”

TBM/MTM for HTS-FNSF: An Innovative Testing Strategy to Qualify/Validate Fusion Technologies for U.S. DEMO

“…The two-machine pathway, shown at the top of Figure 1, is the preferred U.S. pathway to commercial power plant where the first machine would be an FNSF (that could be based on the tokamak, spherical tokamak, or stellarator concept [1]), followed by a DEMO envisioned to be identical in content (i.e., same confinement concept, materials and technologies), but varying in performance The proposed FNSF is a truly integrated high quality test facility. Prior to DEMO construction, fusion power plant components and subsystems must be tested in a dedicated facility with a fusion-relevant environment.…”